1. Field of the Invention
The present invention relates to a video display device for displaying input videos with aspect ratios of 4:3 and 16:9 on a screen longer in a horizontal direction than the one with an aspect ratio of 16:9, e.g. a screen with an aspect ratio of 10:3 in various screen modes.
2. Description of Background Art
A conventional video display device with an aspect ratio of 16:9 is disclosed, for example, in Japanese Unexamined Patent Publication No. H07-135614. This video display device displays an input video with an aspect ratio of 4:3 such as an image of an NTSC video signal in screen modes as shown in FIGS. 13A to 13D.
FIG. 13A shows a state, in the case of a normal screen mode, where an NTSC video NA with an aspect ratio of 4:3 is displayed with accurate circularity without displaying any video at the opposite sides in a horizontal direction of the video display device by conforming the vertical length of the video NA and that of a wide screen WD to each other.
FIG. 13B shows a state, in the case of a wide screen mode, where the NTSC video with an aspect ratio of 4:3 is displayed in conformity with the screen of the video display device with an aspect ratio of 16:9 by displaying the video with an aspect ratio of 4:3 with accurate circularity at a central part of the inputted video while extending the video in a horizontal direction at the opposite sides in the horizontal direction of the video display device.
FIG. 13C shows a state, in the case of a full screen mode, where the NTSC video with an aspect ratio of 4:3 is entirely extended in a transverse or horizontal direction, thereby being displayed in conformity with the video display device with an aspect ratio of 16:9.
FIG. 13D shows a state, in the case of a zoom screen mode, where the NTSC video NA with an aspect ratio of 4:3 is displayed with accurate circularity without displaying any video at the upper and lower sides of the video display device by conforming the horizontal length of the video NA and that of the wide screen WD to each other.
In the conventional video display device with an aspect ratio of 16:9, any desired one of the four screen modes shown in FIGS. 13A to 13D can be, for example, selected, and an NTSC video with an aspect ratio of 4:3 can be displayed in the selected screen mode.
FIG. 14 shows the transition of the screen modes. The respective screen modes shown in FIGS. 13A to 13D are caused to transit from one to another by a toggle, whereby the desired screen mode can be selected to display the NTSC video with an aspect ratio of 4:3.
However, since the aspect ratio is 16:9 in the conventional video display device, there has been a problem of an insufficient number of display aspects with the conventional screen modes in such a video display device laterally longer than the conventional video display device, e.g. the one with an aspect ratio of 10:3.